Parkinson's disease: A current perspectives on Parkinson's disease and key bioactive natural compounds as future potential drug candidates.

Parkinson's disease (PD) is one of the most common types of neurological disorder prevailing worldwide and is rapidly increasing in the elderly population across the globe. The cause of PD is still unknown, but a number of genetic as well as environmental factors contributing to the pathogenesis of Parkinson's disease have been identified. The hallmark of PD includes dopamine deficiency (neurotransmitter imbalance) due to the gradual loss of dopaminergic nerves in the substantia nigra in the midbrain. Studying the mutation of associated genes is particularly informative in understanding the fundamental molecular and pathogenic changes in PD. Intracellular accumulation of misfolded or degraded protein due to mutated gene leads to the manifestation of mitochondrial dysfunction, oxidative stress followed by multifaceted patho-physiologic symptoms. Other studies include the appearance of motor and non-motor responses like resting tremor, muscle stiffness, slow movement and anxiety, anaemia, constipation, rapid eye movement and sleep behaviour disorder. Many bioactive natural compounds have shown positive pharmacological results in treating a number of extensive disease models of PD. Despite the availability of an end number of potent medicinal plants around the world, limited research has been done associated with various neurological disorders, including PD. The currently available dopamine-based drug treatments have several side effects; further, they are not effective enough to combat PD completely. Therefore, various plant-based compounds with medicinal benefits have grabbed lots of attention from researchers to deal with various life-threatening neurodegenerative disorders like PD. On the basis of literature available to date, here, we have discussed and addressed the molecular basis, current scenario, and the best possible treatment of PD for the future with minimal or no side-effects using various key bioactive compounds from natural origin/medicinal plants.